The 44-year-old actor, who has a total of four children, Maya, 15, and Levon, 12, with ex-wife Uma Thurman, and Clementine, six, and Indiana, three, with his current spouse Ryan, said parenthood has made him more reflective.
"Children make you so much more reflective about everything in your life. When I had my older children, I was completely staggered by the magnitude of the experience.
"Maybe you can never be fully prepared to be a father, but I felt like it was fascinating to come to terms with the responsibilities and to structure your world very differently," he said.
"It's still an adventure. I know I'm a much wiser and less self-doubting individual today than I was in my 30s. I had a tough time dealing with everything and I'm so much happier now.